How to create a list of OG groups with no activity using Views?

Question

How can I create a list of OG groups with no activity using Views. For example, the list of groups where users have not created/tagged any content within last 30 days.

Note: We do not have date field attached to Group content-type, the only date associated with groups is group post date.

Answer 1

/**
 * Implements hook_views_pre_render().
 */
function my_module_views_pre_render(&$view) {
  foreach ($view->result as $key => $row) {
    $node = node_load($row->nid);
    if ($node->changed > (time() - (30 * 24 * 60 * 60))) { // 30 days back in time();
    unset($view->result[$key]);
    }
  }
}